Power Plant Environmental Upgrades

The Power Industry in the United States is changing. For years the industry was allowed to release flue gas from the burning of coal into the atmosphere with little or no Environmental Protection Agency (EPA) control. Now, power plant environmental upgrades are being mandated at both the state and federal level to clean up the flue gas; the Clean Coal Initiative, the Mercury and Air Toxics standard, and the Clean Power Plan are just some of the EPA mandates that are affecting the industry. As more EPA regulations are implemented, new technology is being developed to meet the new regulatory requirements. Power plant personnel and management are being tasked with implementing technology that has, in some cases, never been used before. Some of the things being implemented are:

Flue Gas Desulfurization Systems (FGDs) – Systems designed to remove sulfur dioxide (SO2) from the flue gas. SO2 is one of the chemicals that interact with atmospheric water to form sulfuric acid that then falls to earth as acid rain. A typical wet FGD uses a slurry composed of limestone and water that is sprayed counter–current to the flow of the flue gas. The water scrubs the SO2 out of the flue gas causing the formation of sulfuric acid. The sulfuric acid then interacts with the limestone to form gypsum which is then removed as a usable by-product.

Selective Catalytic Removal Systems (SCR) – SCRs are designed to remove another chemical that results from the burning of coal: Nitrous Oxides (more commonly referred to as NOx). NOx has five main forms with NO and NO2 being the most common. Regardless of which form it takes, NOx also combines with atmospheric water to form an acid which then falls to earth as acid rain. The SCR uses a catalyst that is designed to interact with NOx to form Nitrogen and Water. SCRs are extremely efficient in the removal of NOx – usually around 98+% removal efficiency.

Water Treatment Systems – Water has always been a precious commodity but, as the population expands and the distribution of the population across the United States changes, water has to travel further to reach the consumer. At the end of the day, water is becoming scarce. Droughts, population expansions, farming, etc., are having an impact on the amount of water available. Power plants need water to operate. A lot of it! Since it is not efficient to take water and then discharge it into a river or the ocean, the EPA is mandating that a lot of power plants reuse the water that they have. This has led to an expansion of water treatment systems at power plants. Reverse osmosis, settling ponds, clarifiers, gravity filters, etc., are some of the equipment being installed at power plants to clean up the water for reuse or to use a new source such as ocean water, brackish water, or raw river water.

Gypsum Dewatering Systems – Once the FGD is used to scrub the SO2 from the flue gas, gypsum is created as a by-product that must be reclaimed from the slurry water. Gypsum Dewatering systems are used for this purpose. The gypsum laden water is pumped out of the FGD and sent to the Gypsum Dewatering System. Powerful vacuums are used to suck the water out of the slurry, leaving behind a gypsum “cake”. The cake is often washed with either fresh or recycled water to increase the purity of the cake so that the gypsum can be sold or stored on site.

Fly Ash Reclamation Systems – Fly ash is another by-product of burning coal. Think of it as the ash that is left over when you burn anything. Fly ash has typically been efficiently removed from the flue gas by large baghouses and/or electrostatic precipitators. The problem has always been what to do with it after removal. According to the EPA, beneficial uses of fly ash include serving as a raw material in concrete, grout and cement or as a fill material in stabilization projects and road beds. Bottom ash is generally just used as fill or snow control on roads. Around 43% of fly ash in the USA is currently recycled with the largest use by far being the replacement of portland cement. In order to be used in this fashion, it must be “reclaimed”. Large amounts of money and resources are being utilized to reclaim the fly ash. More EPA mandates are being debated due to the accidents at the Dan River in North Carolina and the Kingston Fossil Plant in Roane County, Tennessee.

Combustion Turbine (CT) Generation – Coal has traditionally been the cheapest natural resource for power generation in the United States. Natural gas has simply been too expensive. Now that is changing due to the discovery of new gas fields (or fields not accessible before but are now through horizontal drilling), fracking, and low consumer demand. Gas is cheap. What that means is that it is now cost effective to burn natural gas to produce energy. But coal plants are not very efficient at burning natural gas, so Combustion Turbines are being installed or used instead. A CT is a turbine just like an airplane engine (only MUCH larger) that is connected to a generator to produce electricity.

Alternative Energy – Wind and Solar are being implemented as a viable alternative to coal or natural gas fired plants. As energy storage becomes more efficient, more wind and solar power plants at the grid level are being built. For years, analysts have theorized a future where giant, grid-scale batteries provide a bevy of services for the grid. Teamed up with wind and solar, they could help smooth peaks and troughs in variable generation and store it for use at a later time (read our blog post about solar and wind energy to learn how pumped storage facilities are being used). When aggregated and bid into electricity markets, a fleet of batteries could act as a reliable demand response resource, all the while providing backup power during outages and performing other grid functions like frequency regulation and voltage control. Concentrating Solar Power (CSP) is another new technology that is growing in popularity. Utilizing both solar and traditional power generation the CSP uses mirrors to direct the solar energy onto pipes that are used to heat water to steam which is then used to turn a turbine generator to provide electricity.

Conducting these power plant environmental upgrades through implementation of these new technologies requires an effective training program. The key word is effective. Many times the contract for the environmental upgrade will specify that a certain amount of training must take place prior to commissioning. The vendors supplying the new equipment will often send an engineer or possibly a trainer to fulfill this requirement. However, training is often not an area of expertise for these vendors, and their supplied training can often times be ineffective at preparing plant operators and management for use of the new equipment.

Many plants choose to bring in outside training consultants to come in and deliver training on the new equipment. Unfortunately, this often happens following the vendor supplied designer/builder training when the vendor-supplied training that was given was ineffective. This is completely new technology that most plant employees have never seen before, let alone been asked to operate, which is why it is extremely important for the training to be effective. Since most of the people at the plant have not run these systems, everyone from the management team, engineers, and operators require training that is customized to their systems. Choosing to use training consultants over vendor-supplied training can save the plant both time and money by ensuring the training given is effective the first time around.

Effective training on the environmental upgrades must be tailored to your plant configuration. Generic off-the-shelf training can be misleading and at times completely wrong or outdated. The training must be prepared and implemented on-site and customized to the exact configuration of the plant for it to be effective. The right trainer will spend an extensive amount of time ensuring that the manuals and training used are absolutely correct and customized to you configuration. They will conduct plant visits and interviews, gather references, and talk to and work with both the designer and builders to ensure the information provided to the trainees is complete, correct, and up-to-date.

It is also important to understand that many training consultants do not have experience with the new environmental upgrade technologies listed above, and some do not have experience in the industry at all. When selecting a training consultant for training on your environmental upgrade, ensure that they understand the new technology that is being implemented in the industry. Some consultants have spent decades developing training manuals (sometimes the first of their kind) that are used to train the personnel throughout the industry, while others lack experience. Choosing training consultants that have worked with the industry designers, builders, and the power plant operators to implement training and technical documentation on ALL of the new technologies above will lead to success in operation of the plant following the completion of your power plant environmental upgrade.

Rick Cragg is a project manager at Fossil Consulting Services. Rick spent 20 years in the U.S. Navy running nuclear powered submarines and aircraft carriers and has worked for FCS for 10 years. Rick is the recognized expert on FGDs at FCS, having commissioned and worked on at least 20. Lately Rick has worked on the commissioning of two SCRs in the Hayden/Craig area of Colorado. He provides technical consulting services to utility, independent power, and government clients in the areas of fossil/cogeneration/hydro power plant training needs assessments, program design, development and implementation, as well as auditing of existing programs and materials to ensure compliance with client needs and expectations.